Closed electric furnace



June 3, 1924. 1,496,674

A. HLFENsTl-:IN

CLOSED ELECTRIC FURNACE Filed Fels.' '1, 1922 Patented June 3, 1924.

UNITED STATES PATENT OFFICE.

LOIS HELFENSTEIN. 0F VIENNA, AUSTRIA, ASSIGNOR TO UNIO'N CARBIDE COMPANY, OF NEW YGRK, N. Y., A CORPORATION F VIRGINIA..

CLOSED ELECTRIC FURNACE.

Application led February 7, 1922V To all whom it may conce/m.'

Be it known that I, ALoIs HELFENSTEIN, n citizen of Switzerland, residing at 50 Bas tiongasse XVIII, Vienna.Y Austria, have invented certain new and useful Improvements in Closed Electric Furnaces, of which the following is a specification.

The present invention relates to a closed electric furnace.'

a closed electric furnace, including shafts for continuous charging, in which provision is made for advantageously recovering pure furnace gases.

Briefly stated, the invention consists in disposing the charging ports of the shafts in vthe side Walls of the furnace at points relatively remote from the cover.

The advantages of this arrangement will appear more fully from the description of the invention by reference to the accompanyingT drawings in -whichig. 1 is a vertical transverse section of a furnace embodying the invention;

Fig. 2 is a vertical longitudinal section therefor ;and

Figs. 3, 4 and 5 are vertical transverse sections showing different modifications of which the invention is susceptible.

In Figs. l and 2, is represented a typical furnace construction having an arched roof or cover b. The electrodes a pass through the roof into the char e. The shafts c converge toward each ot. er and pass through the side walls e of the furnace at a considerable distance from the roof b.

The material fed in through the shafts will naturally not level out in the furnace but will bank up along the side walls forming a trough which is deepest along the longitudinal center line.

Due to the particular disposition of the shafts the roof is materially above the charge; and the space f defined by the trough-like surface of the charge, the side walls and the roof, constitutes la chamber of considerable ca aeity for the gases. This chamber natura ly acts as an equalizer in the sense that it takes up and minimizes the surge effects frequently produced by sudden changes in the evolution of gas during the o eration of the furnace.

Fo owing the path `of least resistance the gases rise mainly from the lowest part of the trough-like surface of the charge so that The invention has for its principal object' the furnace wit Serial No. 534,737.

long hot Hnrnes shooting up from the center of the furnace are not likely to reach the side walls or the roof. The arrangement described thus affords a degree of protection not obtainable by other constructions of similar type.

The gases accumulating in the gas space or chamber may be conducted to the dust settler or other receiver through a horizontal Hue IL forming substantially a continuation of space above the trough-like surface of the charge in the furnace.

In the arrangement shown in Fi 3 the electrodes a. extend laterally into thefurnace. In this particular construction, the roof b forms a high arch comprising steep side walls. The shafts c extend downwardly in contiguous relation to the side walls to near the. bottom thereof and have an angular 0rtion passing throu h the side walls. he angular relation oY these portions is substantially the same as that of the shafts 0o in Figs. 1 and 2, sothat the charge in the furnace has a trough-like surface as previously described. The space f defined by the arch of the roof and the char e forms a. gas space which has suhstantiz characteristics as the gas space previously described.

The relation of the shafts and the walls of the furnace in this construction afford a greater utilization of the heat given oil' from the walls of the furnace, principally by radiation, to preheat the material in the shafts.

The construction shown in Fig. 4 is generally like the construction disclosed in Figs. 1 and 2 with the difference, however, that two sets of electrodes ao are employed. In fact the arrangement may be considered as a combination of two furnaces of the type shown in Figs. 1 and 2. The characterist1cs are essentially the same. surface of the charge in' the furnace is somewhat changed due to the differences in c0nstruction, the material presents necessarily a distinctly trou h-like shape lengthwise of the advantages pointed out.

the sha ts for controlling the level of the material in the furnace during operation, since for eicient operation of the furnace the level of the material above the ends of the electrodes must vary as a function of the ly the same It ma be advisable to provide gates a' in While the lll energy` input. While these gates are shown only in'Fig. 4, they are not intended as limited thereto but are generally applicable Ato all the forms. They are referred to in this ligure merely for the sake of convenience.

The form of construction in Fig. 5 is generally similar to the construction shown in Fig. 3. It differs therefrom principally in regard to the manner in whic the gases are conducted away from the gas space f. In this particular construction a shaft extends upwardly from the roof and has an outlet h. Upon a grate n may be placed granular material Z through which the furnace gases are drawn. T e mass of granular material operates to free the gases from dust and particles suspended therein and also cools the gases It is understood that the application of filters is by no means limited to this form of construction. The disclosure in this respect is intended merel as v indicating the genera-l applicability of ust filters in the gas ace outside the furnace and independent o the mixture therein.

Should the as contain carbon dioxide or water vapor, t e filter bed might consist of coke or any other suitable form of carbon, or even of, the furnace mixture itself, in any event giving rise to the well-known reaction between highly heated carbon and carbon dioxide and carbon and water vapor, respectively, thus forming carbon monoxide and hydrogen, a reaction which cools the ga's and at the same time materially enriches 1t In all constructions disclosed, due to the particular arran ement of the shafts, leakage or uncontrol ed How of air into the gas space is practically prevented. The crosssectional area of the shafts is such that the material, under the Weight of the columns therein, continuously passes into the furnace at the rate of consumption' of the charge in the latter.

The arrangement permits of local additions from the ends of the furnace directly into the zone of hottest reaction. The construction also permits stoking the contents of the furnace through the charging shafts or laterally thereof.

Furnaces of the above type find their principal application in the electric smeltmg of calcium carbide, pig iron, etc.; where the reaction of pure car n monoxide is desired, as well as for the production of gaseous products, such as zinc, phosphorus, phosphorous pentoxide and similar sub'- stances which are products of distillation processes.

I claim:

l. The mode of operating a closed electric s furnace, which consists in continuously feeding the material through the side walls at points a substantial distance below the roof thereof inv such a way as to maintain columns of the material above the point of entrance at a height sufficient to prevent entrance of air into the furnace and leakage of,

gas out of the furnace.

2. Th'e mode of operating a closed electric furnace, which consists in continuously and uniformfy feeding the material throu h the lside walls at points a substantial distance below the roof thereof in such a way as to maintain columns of the material above the point of entrance at a height sufficient to revent entrance of air into the. furnace and eakage of gas out of the furnace and furthermore in such a way that the charge in the furnace forms a trough lengthwise of the furnace.

.3. A closed electric furnace comprising charging shafts extending through opposite side Walls at points materially below the roof whereby a gas space is formed above the surface of the charge and the shafts being so disposed that the surface of the char e defines a central trough running lengt wise of the furnace.

4. A closed electric furnace com rising chargin shafts extending through t e side walls o the furnace at a considerable distance below the roof in such a way that the charge passing into the furnace continuousl forms a trou h lengthwise thereof, the sha s bein of suicient height so that the columns o material therein substantially prevent the ingress of air into and the escape of gas from the furnace. g

5. Electric furnace according to claim 4 in, which the cross-sectional area of the shafts is such that the material therein will, under the weight of the columns, continuously pass into the furnace at the rate of consumption of the charge in the latter.

6. Electric furnace according to claim 3 in .which the shafts extend downwardly in intimate heat-exchanging relation to the outer surface of the furnace-walls.

7. A closed electric furnace com rising chargin shafts extending through t e side walls o the furnace, said shafts being of suicient height so that the columns of material therein substantially prevent the iness of air into and the egress of gas from t e furnace, and of suliicient cross-sectional area so that the material therein will, under the weight of the columns, continuously ass into the furnace at the rate of consump ion of the charge in the latter.

8. Furnace according to clailn 7 in which the shafts extend downwardly in intimate heat-exchanging relation to the furnace walls.

9. A' closed electric charging shafts extendin downwardly alon the outer surface of t e side walls in contlguous relation therewith and opening into the furnace at points materially below the roof, the arrangement being such that furnace comprising lll the up er ortion of the side walls and the roof a ordpa relatively lar e gas s ace and that the surface of the c arge efnes a trough lengthwise of the furnace, a conduit 5 connected with the gas space for drawing 0H the gases and means dlsposed in the gas space for fltern the gases.

10. A closed e ectric furnace comprising chargin shafts extending throu h opposite side wa le of the furnace and isposed to cause a banking-up of the material along the side Walls` whereby the charge defines a central trough runningr lengthwise of the furnace and means` for controlling the height of the material in the furnace.

ALOIS HELFENSTEIN. 

